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Ding G, Zhang Z, Chopp M, Li L, Zhang L, Li Q, Wei M, Jiang Q. MRI evaluation of BBB disruption after adjuvant AcSDKP treatment of stroke with tPA in rat. Neuroscience 2014; 271:1-8. [PMID: 24769225 DOI: 10.1016/j.neuroscience.2014.04.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 04/15/2014] [Accepted: 04/17/2014] [Indexed: 12/24/2022]
Abstract
The primary limitation of thrombolytic treatment of ischemic stroke with tissue plasminogen activator (tPA) is the hemorrhagic risk. We tested AcSDKP (N-acetyl-seryl-aspartyl-lysyl-proline), as an auxiliary therapeutic agent, to reduce blood-brain barrier (BBB) disruption in a combination tPA thrombolytic treatment of stroke. Wistar rats subjected to embolic stroke were randomly assigned to either the tPA monotherapy group (n=9) or combination of tPA and AcSDKP treatment group (n=9) initiated at 4 h after ischemia. Magnetic resonance imaging (MRI) measurements were performed before and after the treatments. Immunohistochemical staining and measurements were performed to confirm MRI findings. Longitudinal MRI permeability measurements with gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA) demonstrated that combination treatment of acute embolic stroke with AcSDKP and tPA significantly reduced BBB leakage, compared to tPA monotherapy, at 3 and 6 days (18.3±9.8 mm3 vs. 65.0±21.0 mm3, p<0.001) after the onset of stroke, although BBB leakage was comparable between the two groups prior to the treatments (6.8±4.4 mm3 vs. 4.3±3.3 mm3, p>0.18). The substantial reduction of BBB leakage observed in the combination treatment group was closely associated with reduced ischemic lesions measured by T2 maps (113.6±24.9 mm3 vs. 188.1±60.8 mm3, p<0.04 at 6 days). Histopathological analysis of the same population of rats showed that the combination treatment significantly reduced parenchymal fibrin deposition (0.063±0.059 mm2 vs. 0.172±0.103 mm2, p<0.03) and infarct volume (146.7±35.9 mm3 vs. 199.3±60.4 mm3, p<0.05) compared to the tPA monotherapy at 6days after stroke. MRI provides biological insight into the therapeutic benefit of combination treatment of stroke with tPA and AcSDKP 4h after onset, and demonstrates significantly improved cerebrovascular integrity with neuroprotective effects compared with tPA monotherapy.
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Yin J, Wang L, Shi Y, Shao A, Tang W, Wang X, Ding G, Liu C, Chen S, Gu H. Interleukin 17A rs4711998 A>G polymorphism was associated with a decreased risk of esophageal cancer in a Chinese population. Dis Esophagus 2014; 27:87-92. [PMID: 23895419 DOI: 10.1111/dote.12045] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Esophageal cancer is the eighth most common cancer and sixth leading cause of cancer-associated death worldwide. Besides environmental risk factors, genetic factors might play an important role in the esophageal cancer carcinogenesis. We conducted a hospital-based case-control study to evaluate the genetic effects of functional single nucleotide polymorphisms (SNPs) in the interleukin 17A (IL17A) gene on the development of esophageal cancer. A total of 380 esophageal squamous cell carcinoma (ESCC) cases and 380 controls were recruited for this study. The genotypes were determined using a custom-by-design 48-Plex SNPscan Kit. IL17A rs4711998 A>G polymorphism was associated with the decreased risk of ESCC. When the IL17A rs4711998 AA homozygote genotype was used as the reference group, the AG genotype was associated with a significantly decreased risk for ESCC (AG vs. AA: adjusted odds ratio 0.72, 95% confidential interval 0.53-0.98, P = 0.039). However, there was no significant association between the other five SNPs and ESCC risk. Stratified analyses indicated that a significantly decreased risk of ESCC associated with the IL17A rs4711998 A>G polymorphism was evident among younger patients and patients who never smoking or drinking. These findings indicated that functional polymorphism IL17A rs4711998 A>G might contribute to ESCC susceptibility. However, our results were obtained with a limited sample size; the power of our analysis was low. Future larger studies with more rigorous study designs of other ethnic populations are required to confirm current findings.
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Jiang Y, Luo Q, Gao Q, Ding G, Sheng J, Huang H. Intrauterine high-glucose environment influences placental development through imprinting regulation of Dlk1/Gtl2 region. Fertil Steril 2013. [DOI: 10.1016/j.fertnstert.2013.07.1826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ding G, Tian Y, Zhang Y, Pang Y, Zhang JS, Zhang J. Application of a global reference for fetal-weight and birthweight percentiles in predicting infant mortality. BJOG 2013; 120:1613-21. [PMID: 23859064 DOI: 10.1111/1471-0528.12381] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2013] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To determine whether the recently published A global reference for fetal-weight and birthweight percentiles (Global Reference) improves small- (SGA), appropriate- (AGA), and large-for-gestational-age (LGA) definitions in predicting infant mortality. DESIGN Population-based cohort study. SETTING The US Linked Livebirth and Infant Death records between 1995 and 2004. POPULATION Singleton births with birthweight >500 g born at 24-41 weeks of gestation. METHODS We compared infant mortality rates of SGA, AGA, and LGA infants classified by three different references: the Global Reference; a commonly used birthweight reference; and Hadlock's ultrasound reference. MAIN OUTCOME MEASURES Infant mortality rates. RESULTS Among 33 997 719 eligible liveborn singleton births, 25% of preterm and 9% of term infants were classified differently for SGA, AGA, and LGA by the Global Reference and the birthweight reference. The Global Reference indicated higher mortality rates in preterm SGA and preterm LGA infants than the birthweight reference. The mortality rate was considerably higher in infants classified as preterm SGA by the Global Reference but not by the birthweight reference, compared with the corresponding infants classified by the birthweight reference but not by the Global Reference (105.7 versus 12.9 per 1000, RR 8.17, 95% CI 7.38-9.06). Yet, the differences in mortality rates were much smaller in term infants than in preterm infants. Black infants had a particularly higher mortality rate than other races in AGA and LGA preterm and term infants. CONCLUSIONS In respect to the commonly used birthweight reference, the Global Reference increases the identification of infant deaths by improved classification of abnormal newborn size at birth, and these advantages were more obvious in preterm than in term infants.
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Wang H, Reilly KH, Smith MK, Brown K, Jin X, Xu J, Ding G, Zang C, Wang J, Wang N. Herpes simplex virus type 2 incidence and associated risk factors among female sex workers in a high HIV-prevalence area of China. Int J STD AIDS 2013; 24:441-6. [PMID: 23970745 DOI: 10.1177/0956462412472800] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Herpes simplex virus type 2 (HSV-2) can contribute to the spread of HIV. From March 2006 to November 2009, female sex workers (FSWs) in Yunnan, China were recruited into an open cohort study to determine incidence and risk factors for HSV-2 acquisition. Participants were interviewed and tested for HSV-2 and other sexually transmitted infections (STIs) every six months. A multivariate Cox proportional hazards regression model with time-dependent variables was used to measure associations with HSV-2 acquisition. In 3.5 years, 83 incident cases of HSV-2 infection were diagnosed, yielding an overall incidence of 21.9 per 100 person years (PY) (95% confidence interval [CI], 17.8-26.3). Working in higher risk commercial sex venues, current Neisseria gonorrhoeae infection, age of sexual debut <18 years and lack of a regular sex partner were independent factors associated with HSV-2 acquisition. The high incidence of HSV-2 suggests that prevention methods for HIV/STI control are urgently needed.
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Gao J, Xu YY, Li FW, Ding G. Production of S-acetoin from diacetyl by Escherichia coli transformant cells that express the diacetyl reductase gene of Paenibacillus polymyxa ZJ-9. Lett Appl Microbiol 2013; 57:274-81. [PMID: 23701367 DOI: 10.1111/lam.12107] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 05/16/2013] [Accepted: 05/18/2013] [Indexed: 12/01/2022]
Abstract
UNLABELLED S-acetoin (S-AC) is an important four-carbon chiral compound that has unique industrial applications in the asymmetric synthesis of valuable chiral specialty chemicals. However, previous studies showed that the usually low yield and optical purity of S-AC as well as the very high substrate cost have hindered the application of this compound. In the current work, a gene encoding diacetyl reductase (DAR) from a Paenibacillus polymyxa strain ZJ-9 was cloned and expressed in Escherichia coli. Whole cells of the recombinant E. coli were used to produce S-AC from diacetyl (DA). Under optimal conditions, S-AC with high optical purity (purity >99·9%) was obtained with a yield of 13·5 ± 0·24 and 39·4 ± 0·38 g l(-1) under batch and fed-batch culture conditions, respectively. This process featured the biotransformation of DA into S-AC using whole cells of engineered E. coli. The result is a considerable increase in the yield and optical purity of S-AC, which in turn facilitated the practical application of the compound. SIGNIFICANCE AND IMPACT OF THE STUDY This study demonstrated a highly efficient new method to produce S-acetoin with higher than 99·9% optical purity from diacetyl using whole cells of engineered Escherichia coli. It will therefore decrease the production cost of S-acetoin and highlight its application in asymmetric synthesis of highly valuable chiral compounds.
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Ding G, Luo G. SU-E-J-163: The Imaging Dose to Patients Result
ing From the ExacTrac X-Ray System. Med Phys 2013. [DOI: 10.1118/1.4814375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Pawlowski J, Ding G. SU-E-T-555: A Model-Based Dose Calculation Algorithm for Kilovoltage X-Rays. Med Phys 2013. [DOI: 10.1118/1.4814984] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Hisey K, Morales-Paliza M, Ding G. SU-E-T-168: A Feasibility Study to Use Gamma-Histogram Analysis in Assisting Quality Assurance Criteria for Evaluating Volumetric Modulated Arc Therapy Treatment Plans. Med Phys 2013. [DOI: 10.1118/1.4814603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Ding G, Krauss R. SU-E-T-544: An Empirical Formula to Obtain Tissue-Phantom Ratios From Percentage Depth Dose Curves for Small Fields. Med Phys 2013. [DOI: 10.1118/1.4814974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Nelson A, Ding G. SU-E-I-11: A Simple Approach to Account and Report Organ Dose From KV Image Guidance Procedures. Med Phys 2013. [DOI: 10.1118/1.4814111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Hadley A, Ding G. SU-E-T-599: A Dosimetric Comparison Between Multiple Junction Shifts and Single Gradient Dose Junction for Craniospinal Irradiation (CSI). Med Phys 2013. [DOI: 10.1118/1.4815027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Morales-Paliza M, Ding G. SU-E-T-13: An Evaluation of RadCal Software in Its Monitor Unit Calculation Accuracy for Small Dynamic Fields Using HDMLC. Med Phys 2013. [DOI: 10.1118/1.4814447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Tierney K, Coffey C, Morales M, Ding G. SU-E-T-45: Maximizing the Spatial Resolution of the MatriXX Device for Radiosurgery Plan QA. Med Phys 2013. [DOI: 10.1118/1.4814480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Wang L, Ding G. SU-E-T-545: The Accuracy of the Out-Of-Field Dose Calculations of a Commercial Treatment Planning System. Med Phys 2013. [DOI: 10.1118/1.4814975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Yao Y, Yang F, Chu J, Siame G, Lim HJ, Jin X, Ding G, Sun Y, Wang G, Yu Y, Wang N. Associations between drug use and risk behaviours for HIV and sexually transmitted infections among female sex workers in Yunnan, China. Int J STD AIDS 2013; 23:698-703. [PMID: 23104743 DOI: 10.1258/ijsa.2012.011346] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This is a cross-sectional study of 399 subjects conducted to explore the association between drug use and risk behaviour for HIV and sexually transmitted infections (STIs) among female sex workers (FSWs), and also to study the prevalence of HIV/STIs among drug-using FSWs (DUFSWs) and non-DUFSWs in Yunnan province of China. Demographic information, mobility, sexual and drug-using behaviours were collected and subjects were tested for HIV/STIs. Mean age was 27 years (SD = ±7.8) and 94 (23.6%) tested positive for recent opiate use. Compared with non-DUFSWs, DUFSWs had a significantly higher prevalence of HIV (38% versus 4%, P ≤ 0.001), herpes simplex virus type 2 (HSV-2; 92% versus 60%, P ≤ 0.001) and STIs (95.7% versus 69.2%, P ≤ 0.001). DUFSWs had a significantly longer duration of commercial sex work compared with non-DUFSWs (median 5 versus 1 years, P ≤ 0.001), and had at least two clients in the last working day. DUFSWs were also more likely to work in low-end commercial sex venues and frequented a greater number of work locations than non-DUFSWs. Compared with non-DUFSWs, DUFSWs were more likely to exhibit riskier sexual behaviours and greater workplace mobility. Interventions targeting drug-related behavioural changes are needed urgently in this population in order to reduce rates of HIV and STIs.
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Ding G, Zhang D, Yu Y, Zhang B, Zhao L. Molecular characterization and population genetic diversity of Limonium sinense based on nuclear ribosomal DNA and ISSR. RUSS J GENET+ 2013. [DOI: 10.1134/s1022795413050049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Ding G, Zhang D, Yu Y, Zhang B, Zhao L. Molecular characterization and population genetic diversity of Limonium sinense based on nuclear ribosomal DNA and ISSR. GENETIKA 2013; 49:626-631. [PMID: 24159804 DOI: 10.7868/s0016675813050044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The single nucleotide polymorphism (SNP) and amplification refractory mutation system (ARMS) have been applied to authenticate Limonium species and their corresponding herb samples. One species specific primer was designed and the amplification product is 200 bp (Limonium sinense) by using this primer. No band was observed with other Limonium species. The phylogenetic relationship of Limonium species were studied using ribosomal DNA ITS and the adulterants (L. bicolor, L. aureum and L. wrightii) were clustered with L. sinense in NJ tree. Inter simple sequence repeat (ISSR) was used to assess genetic diversity and population structure of L. sinense and a high level of genetic diversity was detected (H(E) = 0.2573, PPB = 85.71%) with POPGENE. Based on AMOVA analysis, there was moderate variation between pairs of populations with phi(ST) from 0.1744 to 0.5131 and on average 28.81% of the genetic variation occurred among populations. Five main clusters were shown in UPGMA dendrogram using TFPGA. The results showed that SNP and ARMS could be used to authenticate not only Limonium species but related herbs on rDNA internal transcribed spacer region. Possible strategies should be implemented for conservation of this endemic herb.
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Ding G, Liu F, Feng C, Xu J, Ding Q. [Association between the myeloperoxidase gene polymorphisms and the susceptibility to prostate cancer: a case-control study in a Chinese population]. Actas Urol Esp 2013; 37:79-82. [PMID: 23260186 DOI: 10.1016/j.acuro.2012.03.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 03/10/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND AND OBJECTIVES Prostate cancer (PCa) is the most common cancer among men in most western populations. The polymorphisms of the myeloperoxidase (MPO) gene have been correlated with abnormal MPO expression and increased risk of various types of cancers. Our study aimed to evaluate the association between the genetic polymorphisms and the risk of prostate cancer. METHODS Genotyping was carried out by using the genotyping system (MassARRAY iPLEX; Sequenom, Inc., San Diego, CA, USA) on 1,108 PCa patients and 1,525 cancer-free controls in a Chinese Han population. RESULTS Although one SNP (rs8082134, P < 0.050) was significant, it is very rare and unstable. Other SNPs had no significant difference between genotype distributions in the PCa patients and the control group. Totally, SNPs in the MPO gene is not associated with PCa risk. CONCLUSION Our data showed a limited association between the MPO SNPs and the susceptibility to PCa in population of Chinese Han population. The possible association of rs8082134 of MPO with PCa risk need further clarification.
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Che J, Tian M, Ding G, Huai Q, Dong P, Li Y, Li S. Effects of cell salvage on erythrocyte 2,3-disphosphoglycerate and G-6-PD levels and phosphatidylserine expression. Int J Lab Hematol 2012; 35:385-92. [PMID: 23176294 DOI: 10.1111/ijlh.12028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Accepted: 10/16/2012] [Indexed: 11/29/2022]
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Gu J, Ding G, Chen N, Zhang Z. LC-MS-MS Determination and Pharmacokinetic Study of the Novel Anti-Tumor Candidate Drug TEOA in Rats. J Chromatogr Sci 2012; 51:496-501. [DOI: 10.1093/chromsci/bms176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Ding G, Zhang D, Ding X. Isolation and characterization of microsatellite markers in Chinese herb of Dendrobium loddigesii. RUSS J GENET+ 2012. [DOI: 10.1134/s1022795412080030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Ding G, Zhang D, Ding X. Isolation and characterization of microsatellite markers in Chinese herb of Dendrobium loddigesii. GENETIKA 2012; 48:1237-1240. [PMID: 23270273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
As an invaluable herb, Dendrobium loddigesii is widely used in Chinese medicinal field. In order to develop a convenient and efficient identification method and investigate the genetic diversity and structure of this species, twelve microsatellite loci were isolated from two microsatellite-enriched libraries. Twenty-six individuals from Baise population were analysed. The observed and expected heterozygosities ranged from 0.174 to 0.617 and from 0.182 to 0.608, respectively. These microsatellite loci characterized from D. loddigesii will contribute to research on the individual authentication, population structure, genetic diversity and conservation of this species and its similar species.
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Nelson A, Ding G. SU-E-I-09: Patient Organ Doses from KV-CBCT Acquisitions as Function of Patient Size and Scan Protocols. Med Phys 2012; 39:3626. [DOI: 10.1118/1.4734723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Ding G, Munro P. SU-E-J-39: Minimizing IGRT Imaging Exposures: KV Radiograph Vs. KV-CBCT Vs. MV Portal Images. Med Phys 2012; 39:3661. [PMID: 28517604 DOI: 10.1118/1.4734874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To compare the IGRT doses from MV, kV and CBCT images. METHODS kV imaging systems integrated into Varian Trilogy and TrueBeam accelerators were modeled using BEAMnrc/DOSXYZnrc Monte Carlo codes and the dose to calibration phantoms for a variety of kV beams(kVp, bow-tie filters, etc.) were calculated. The doses to the same phantoms and kV beams were then measured experimentally using calibrated ion-chambers.The "calibrated" Monte Carlo kV beams were used to calculate dose to CT images of patients. Organ doses were analyzed using DVHs. RESULTS The doses to the prostate are 0.015 and 2.2cGy using AP kV and MV images; are 0.06 and 2.3cGy using lateral kV and MV images; and, are 1.7 cGy using CBCT images. For head and neck images, the doses to the eye are 0.08 and 0.001 cGy using AP and PA kV images; are 2.3 and 1.8cGy using AP and PA MV images; are 0.001 and 2.4cGy for lateral kV and MV images; and, are 0.2 cGy for CBCT images. For kV radiographs, organ doses can be further reduced, by over 30%, by using bow-tie filters. CBCT doses to the prostate are 1.6 and 0.9cGy for OBI and TrueBeam pelvis scans; a >40% dose reduction for the same image quality. For OBI CBCT head scans the doses to the eye and brain stem are 0.2 and 2.8cGy, respectively. CONCLUSIONS Due to the low penetration of kV beams,selecting beam angles so that the sensitive organs are near the beam exit, and/or using bow-tie filters, can substantially reduce organ doses when using kV radiographs. For daily positioning of pediatric brain patient with a set of orthogonal kV images, a CBCT scan, or a set of orthogonal MV images, the doses to the eyes are 0.1, 0.2, and 4.7 cGy, respectively.
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